The present invention relates to an electronic musical instrument having a tone generator of simplified circuit configuration.
Conventional electronic organs generally comprise a tone generator for generating a plurality of octave tone signals, a keying unit associated with the keyboard for selecting an octave signal in response to a struck key and a filter unit through which the keyed signal is applied to a speaker or speakers. The prior art tone generator comprises an oscillator, a plurality of first frequency dividers each of which is coupled to the oscillator for generating a tone of definite pitch so that a set of tones from C# note to C note is simultaneously generated from the tone generator. Associated with each of the first frequency dividers is a series of interconnected divide-by-two counters for dividing the frequency of the generated tone in succession to generate a set of octave tones. Through a connecting network the octave tone signals of each note are applied to plural keying circuits which, in response to the information from the keyboard, generates 2' (feet), 4', 8' and 16' signals.
Because of the great number of circuit components required to build the tone generator and the keying unit and because of the simultaneous generation of various tones, the prior art electronic organ is expensive to manufacture and consumes a substantial amount of energy. Since for most musical performances only a few notes are usually required at a given instant, the circuits are not efficiently utilized and a substantial part of the tone generating energy is wasted.
Attempts have hitherto been made to simplify the electronic circuit of the organ. However, no satisfactory results have been achieved.